Designated 'Molecule of the Year' in 1992 in recognition of its many biological roles, nitric oxide has wide significance in the world around us and the story of nitric oxide is still unfolding. This small and seemingly innocent molecule has for many years been known to play a significant role in both the creation of photochemical smogs and in the nitrogen cycle. It has an interesting chemistry as a metal ligand, and the bonding within the nitric oxide molecule has been extensively studied. More recently, the molecule has been in the spotlight for the role it plays in controlling blood flow,...